Roku Premiere+ not in Cast device list on Android Plex App if channel not selected
I have a brand new Roku Premiere+ updated to latest version with PLEX channel installed. I have an Android Nexus 6 phone with PLEX App and when I try to "Cast" the Roku is not listed in the available devices list. If I manually open the Plex channel on the roku, it appears on my phone.
I tested with Youtube and I don't have to pre-select the channel. Is this a bug? Do I have to configure something?